dblaikie added a comment. In D146595#4235340 <https://reviews.llvm.org/D146595#4235340>, @augusto2112 wrote:
> In D146595#4235333 <https://reviews.llvm.org/D146595#4235333>, @aprantl wrote: > >> I hope I'm not kicking off a long bike-shedding thread, but I would propose >> to either call the attribute `transparent` to match the DWARF attribute >> name, or if we want to be more descriptive, `debug_transparent`, or >> `transparentdebug` to fit better with other attributes such as `nodebug`. My >> vote is on `transparent`. > > The dwarf attribute is actually called `trampoline`, not `transparent`. > `trampoline` is a pretty generic name which could be used for other things > other than debugging, so maybe `trampolinedebug`? FWIW, trampoline seems weird to me (both for the DWARF attribute, and the source level attribute) - my understanding is that trampolines are small functions that just immediately jump to some other function. In this case the intermediate function can be arbitrarily complicated, but just not /interesting/ to the average developer. Doesn't seem like a trampoline to me. (though maybe I'm thinking of a "thunk" specifically - at least wikipedia's deefinition of a programming trampoline is fairly broad/involves some fairly higher level "do some non-trivial things" operations, I guess) I guess an example of something that might be transparent but not trampoline-like would be std::sort - the ability to step into the comparison function, but skip over the actual sorting logic (or for_each, etc - you might want to step into your functor, but skip the intermediate logic that's handling the looping, etc). Those don't feel like trampolines, I guess? In D146595#4241852 <https://reviews.llvm.org/D146595#4241852>, @aprantl wrote: >> Is there some place (bug, discourse thread, etc) where the broader direction >> is discussed? I want to checkin on the design decisions/alternatives without >> fragmenting this across multiple reviews/losing context/etc? > > No, I believe that all the relevant discussion happened in this review. While > there is a separate review for an LLDB implementation, there is no general > direction discussion there, it's just implementing a DWARF feature. Thanks, sorry, gets all a bit confusing sometimes :/ >> (specifically - this started out with the trampoline attribute, then >> switched to this transparent idea (perhaps based on my feedback? Also other >> feedback? I'd like to know more about how that change in direction happened, >> what the tradeoffs were, etc - I don't think my suggestion alone was >> probably enough to make this direction clearly the right one (nor clearly >> the wrong one)), etc) > > It was partially based on your feedback, but also on @arphaman pointing out > that the `DW_AT_trampoline("call_target")` implementation wouldn't be able to > deal with the jump target being a virtual function call. So @augusto2112 > landed on implementing the "flag variant" of `DW_AT_trampiline` instead. This > is also an existing DWARF feature, albeit not yet supported by LLVM. OK >> & there was some tangent about DWARF v COFF too, which I wouldn't mind >> weighing in on, but feel like it's all a bit fragmented, so not sure where >> all the discussions are/how to keep track of them. > > That was also in this review; @aaron.ballman pointed out that it would be > best if new Clang attributes weren't targeting only DWARF, though I believe > this request may run into some hard limitations of what CodeView/PDB can > support. Yeah, that seems like a bit of a big ask, since there's a specific DWARF feature we're lowering to here - feels out of scope to go trying to figure out how it might be implemented in CodeView. For features that are format-agnostic (like simple template names, no-standalone-debug (various type homing strategies), etc) yeah, makes total sense for them to be format-agnostic. This isn't one of those, though. but, I guess, worth at least asking the question if there's an equivalent feature in CV already that this should be mapped to Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D146595/new/ https://reviews.llvm.org/D146595 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
